1. Field of the Invention
The present invention relates to a method and an apparatus for easily sintering a silver clay composition.
2. Description of the Related Art
In general, silver clay is obtained by mixing a powder of pure silver or silver alloy with binder and the like. An accessory is manufactured by heating and sintering a silver clay composition which is obtained by forming the silver clay to a predetermined shape and drying it in an electric furnace or a gas furnace whose heating temperature can be controlled.
While the above electric furnace or the gas furnace is relatively suited to sinter a lot of work pieces simultaneously since the furnace is relatively large, it is difficult for an individual worker to prepare this type of furnace. Accordingly, a sintering method in which the silver clay composition is inserted into a sintering box which absorbs microwave and generates heat, and is sintered by setting the sintering box in a household microwave oven has been proposed recently. However, this sintering method is inconvenient since the special sintering box which absorbs microwave and generates heat has to be prepared. Furthermore, since temperature control is difficult and the heating condition of the silver clay composition in the sintering box cannot easily be observed, occasionally the clayish composition melts due to excessive heat beyond a melting point thereof.
In addition, a sintering method for the silver clay in which the silver clay composition is sintered by being directly exposed to the flame of a gas burner has been proposed recently (see Japanese Patent Application, First Publication No. 2000-80404). In this method, the flame of the gas burner can be freely controlled and the silver clay composition can be sintered anywhere merely by preparing a portable gas bottle and a gas burner.
However, in the method in which the silver clay composition is sintered using the gas burner, the gas burner is generally used without a cover and thus the flame of the gas burner is visible whole the sintering operation. In this case, the flame of the gas burner often ignites explosively even though it can be controlled, and as a result, when a person uses the burner, the desire to manufacture an accessory by heating the silver clay may be dampened due to a fear of the gas burner. While a method in which the silver clay composition is heated and sintered by the flame of the gas burner in a receptacle that is made of a fireproof material has been proposed, however, in the case of performing the sintering in the receptacle, the operability is decreased unless the space in the receptacle is enlarged so that the gas burner can be moved within the receptacle. As a result, the receptacle becomes larger, and therefore, labor for installing the receptacle and a space for storing the receptacle after the sintering operation are necessary.
Furthermore, though the gas burner is convenient in that the flame thereof can be freely controlled, it is difficult to adjust the temperature of the flame to the optimum temperature for the sintering of the silver clay composition. Therefore, the temperature of the flame often deviates from the optimum temperature for the sintering of the silver clay composition as a result of controlling of the flame. Consequently, it is difficult to obtain desired accessories.